Enthalpies of Mixing in Some Binary Alkaline‐Earth Chlorides

1967 ◽  
Vol 47 (6) ◽  
pp. 2014-2020 ◽  
Author(s):  
G. N. Papatheodorou ◽  
O. J. Kleppa
Keyword(s):  
Alkaline Earth ◽  
Enthalpies Of Mixing ◽  
Binary Alkaline ◽  
Alkaline Earth Chlorides

Fluorescence of Eu2+‐Activated Binary Alkaline Earth Silicate

1986 ◽  
Vol 133 (3) ◽  
pp. 657-660 ◽  
Author(s):  
K. Yamazaki ◽  
H. Nakabayashi ◽  
Y. Kotera ◽  
A. Ueno
Keyword(s):  
Alkaline Earth ◽  
Binary Alkaline

Diffusion of alkali and alkaline earth chlorides through a parchment-supported silver iodide membrane

1972 ◽  
Vol 25 (9) ◽  
pp. 1837 ◽  
Author(s):  
Beg M Aijaz ◽  
S Pratap
Keyword(s):  
Silver Iodide ◽  
Alkaline Earth ◽  
Diffusion Rate ◽  
Activation Parameters ◽  
Weak Field ◽  
Thermodynamic Quantities ◽  
Constant Flow ◽  
Ion Hydration ◽  
Diffusion Rates ◽  
Alkaline Earth Chlorides

Diffusion rates of KCl, NaCl, LiCl, BaCl2, CaCl2, and MgCl2 through a parchment-supported silver iodide membrane have been measured at various temperatures using a constant flow method. Activation energies and various Eyring activation parameters for the diffusion of these electrolytes have also been evaluated. The diffusion rate sequences obtained are KCl > NaCl > LiCl and BaCl2 > CaCl2 > MgCl2 and they point towards the weak field strength of the membrane fixed charged groups. Diffusion coefficients and the various Eyring activation parameters have been related to the ionic hydrated sizes and the various thermodynamic quantities of ionic hydration thus emphasizing the importance of ion hydration in diffusion across the membrane.

Gemischte Erdalkalimetall-Trielide AIIM1IIIx M2 III2– x (AII = Ca, Sr, Ba; MIII = Al, Ga, In). Strukturchemische und bindungstheoretische Untersuchungen / Mixed Alkaline Earth Trielides AIIM1IIIx M2III2−x (AII = Ca, Sr, Ba; MIII=Al, Ga, In). A Structural and Theoretical Study

2007 ◽  
Vol 62 (2) ◽  
pp. 177-194 ◽  
Author(s):  
Wiebke Harms ◽  
Marco Wendorff ◽  
Caroline Röhr
Keyword(s):  
Alkaline Earth ◽  
Structural Changes ◽  
General Structure ◽  
Structure Type ◽  
Laves Phases ◽  
Stability Range ◽  
The Stability ◽  
Binary Alkaline ◽  
Structure Calculations ◽  
Stability Ranges

The binary alkaline earth trielides of the composition AIIMIII 2 exhibit a puzzling variety of structure types ranging from electron precise Zintl compounds like CaIn2 and KHg2 (both with networks of four-bonded M− entities) and the AlB2 structure type (with graphite analogue M sheets) to the cubic Laves phases e. g. of CaAl2. The examination of the phase stabilities of mixed compounds AM1IIIx M2III2−x of two trielides allows to separate the stability ranges in a structure map by taking the electronegativity differences of MIII and AII (Δ EN) and the radius ratios (RR = rM/rA) into account: The CaIn2-type is stable at comparatively large RR, for example over the whole range CaGa2 -CaIn2 and even up to CaAl0.6Ga1.4 and CaAl1.2In0.8, and in SrIn2, together with a limited substitution of In by Al or Ga. The KHg2-type is observed in a region of lower RR: In BaIn2, a substitution of In by 50% Al and 30% Ga is possible without a general structure change, in SrAl2 this holds for a content of up to 50% In. At high Δ EN and low RR values (e. g. Sr/Ba-Ga), the ideal AlB2 structure type exhibits a distinct stability range; only for small RR around CaAl2 the MgCu2-type is stable. FP-LAPWband structure calculations of the binary trielides allow to explain the structural changes qualitatively. In the case of the electron precise phases forming the CaIn2, KHg2 or AlB2 structure type, details of the bonding situation (such as M-M distances) as well as differences to other isoelectronic compounds can be rationalized taking the incomplete charge transfer from the alkaline earth towards the triel elements into account. This causes a partial depopulation of some of the bonding and a population of predominantly antibonding states.

Structure of Zirconia Nanoparticles used for Pillaring of Clay

2001 ◽  
Vol 703 ◽  
Author(s):  
V. A. Sadykov ◽  
T. G. Kuznetsova ◽  
V. P. Doronin ◽  
T. P. Sorokina ◽  
D. I. Kochubei ◽  
...  
Keyword(s):  
Alkaline Earth ◽  
Nitrogen Adsorption ◽  
Structural Features ◽  
Concentration Addition ◽  
X Ray ◽  
Oxygen Anions ◽  
Nitrogen Adsorption Isotherms ◽  
Alkaline Earth Chlorides ◽  
Zirconium Concentration ◽  
Zirconia Nanoparticles

ABSTRACTSAXS and EXAFS were applied to study genesis of polynuclear zirconium hydroxyspecies in pillaring solutions as dependent upon the zirconium concentration, addition of alkaline-earth chlorides and aging. After the montmorillonite clay pillaring, the structure of zirconium nanopillars was characterized by applying X-ray structural analysis, UV-Vis, FTIRS of adsorbed CO and nitrogen adsorption isotherms. Main pillaring species appear to be nanorods comprised of several Zr4 tetramers. Basic structural features of the tetramers are preserved in zirconia nanoparticles fixed between alumosilicate layers in pillared clays. In calcined samples, those nanoparticles contain only bridging hydroxyls and/or oxygen anions responsible for bonding within pillars and between pillars and clay sheets.

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